Interpretive Summary: FDA allowed the use of ionizing radiation for the control of foodborne pathogens and extension of shelf-life in fresh Iceberg lettuce and spinach up to a maximum absorbed dose of 4.0 kilogray. However, whether irradiation will cause undesirable changes on quality of spinach is unclear. This study was conducted to investigate the effect of gamma radiation at doses up to 4 kilogray nutritional and sensory quality of fresh-cut spinach during post-irradiation storage. Our results suggest that irradiation at doses up to 2 kilogray did not significantly affect sensory properties, overall antioxidant capacity or consumers’ purchase intent of spinach. The information is useful for produce industry to consider irradiation as an intervention technology to improve microbial safety of spinach.

Technical Abstract:
The use of ionizing radiation to enhance microbial safety of fresh spinach at a maximum dose of 4 kGy has been approved by the U.S. Food and Drug Administration. However, whether spinach can tolerate those high doses of radiation is unclear. Therefore, this study was conducted to investigate effects of irradiation doses on nutritional and sensory quality of fresh-cut spinach. Results showed that none of the sensory properties or purchase intent was affected by irradiation at doses up to 2 kGy. The oxygen radical absorbance capacity (ORAC) values and total phenolic content were not consistently affected by irradiation either. However, ascorbic acid content of irradiated sample decreased rapidly during storage, resulting in all irradiated samples being lower in ascorbic acid content after 7 and 14 days of storage at 4C. Therefore, irradiation at doses up to 2 kGy may be used to enhance microbial safety without affecting consumer acceptance or overall antioxidant values of irradiated spinach.